The functions of this Core Facility are to employ flow cytometric analysis and fluorescence activated cell sorting to solve problems in cancer research. The Core Facility provides comprehensive support of this technology in order to facilitate utilization by a variety of investigators. Specifically, the Core facility: A. maintains a state-of-the-art dual laser flow cytometer/cell sorter which is the only flow cytometer with cell sorting capability at Georgetown UniVersity; B. provides a trained operator to insure efficient and correct use of this complex instrumentation; C. provides personnel to assist with the development and application of a variety of fluorescence labeling methods; D. provides expertise for the innovative application of this instrumentation in order to fully exploit the capabilities of this technology for cancer research. Sixty-one investigators (57 LCRC members) from 13 different departments at Georgetown have used this Core Facility since the instrument was installed in 1989; 25 LCRC investigators with peer reviewed funding utilized this facility during the past year (July 1, 1991 to June 30, 1992).